Merco Insta-Therm 16000 Series, Parts & Service Manual

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Insta-Therm Service Manual 5
SEQUENCE OF OPERATION
POWER SUPPLY
Electrical power is supplied to the unit by a 3 conductor service for single phase.
Black conductor is hot.
White conductor is neutral.
Green and Yellow conductor is ground.
Power is permanently supplied to the power switch through the high limit
thermostat. Also to the open contacts of the main power relay.
HEATING CIRCUIT Closing the main power switch feeds power to the cooling fan and the coil of the
main power relay. Its contacts now close supplying 50% power to the 4 heaters
through the current limiting solid state relay.
When product is placed on the shelf, the normally open contact (S2) closes to
supply full power through the current limiting solid state relay and two indicator
lamps to the heaters.